Hi @Noffil.c ,

You can easily achieve this by using inline scripts like Python, Java or C#.

Let me know if you need further details on this. 

Else, you can utilize the String → Find action and use the expression rA-Z] and store the result into a number type variable. Later by using the If-Else condition, you can find if there is any Capital letter available in the source string or not.

Please note: The String→ Find action will return only the position of first matching letter and not the letter itself.